Norwegian Foreign Ministry spokesman Frode Andersen says Dmitry Rogozin's visit was "regrettable," and demanded an explanation as the ministry had informed the Russian Embassy in Oslo earlier this year that people on the sanctions list "are not wanted on Svalbard."

Rogozin's Twitter account on Saturday carried a photo of him purportedly in Svalbard with the text "arrived in Longyearbyen on Svalbard."

Andersen said Sunday that the demand to the Kremlin was made late Saturday to the embassy in Oslo, and that Norway was considering "to reinforce measures for travel to Svalbard." He didn't give details.